In-the-ear and in-the-canal type hearing aids have become accepted by the hearing impaired public for their small size, ease of use and relative comfort, as compared to older style hearing aids. Many of the in-the-ear and in-the-canal type devices include a shell which is designed to fit in the ear or ear canal of the user.
The shell may hold the electronic circuitry, a microphone, and a receiver. The microphone receives sound signals from outside of the device and responsively creates an electronic signal. The signal may be sent to an amplifying circuit which supplies a signal to the receiver. The receiver in turn, provides audio output to the ear.
Typically, in the in-the-ear and in-the-canal type devices, sound travels from an output port of the receiver, through a sound channel, and out of the device through an acoustical output port in the hearing aid shell. The sound may then travel through the user's ear and cause the tympanic membrane to vibrate.
The ears secrete a substance known as cerumen or ear wax. While ear wax cleans the internal structure of the ear, it also tends to flow into the sound channel and receiver of a hearing aid located in the ear. Ear wax which migrates into a hearing aid can degrade the effectiveness of the device and can eventually cause the device to fail.
A number of barrier products are presently available to prevent or reduce the migration of ear wax into a hearing aid. One such barrier design uses a fine mesh screen in the sound channel between the receiver and acoustical output port of the shell. While such a barrier reduces the migration of ear wax into the hearing aid, it suffers from the possibility of becoming clogged with wax.
More recently, barrier systems have been introduced which include a housing which threadedly interconnects the output port of the receiver and the acoustic port of the shell. The housing threads into a portion of the shell. The housing has an interior surface which includes projections extending inwardly thereof, creating a tortuous path for solid or semi-liquid ear wax migrating therethrough.
Such devices are disclosed in Weiss, U.S. Pat. No. 4,870,689, entitled "Ear Wax Barrier For A Hearing Aid" and Weiss et al., U.S. Pat. No. 4,972,488, entitled "Ear Wax Barrier And Acoustic Attenuator For A Hearing Aid," both of which patents are commonly assigned herewith, and both of which patents are hereby incorporated by reference.
In the devices disclosed in the Weiss and Weiss et al. patents, the barrier is incorporated into a housing, which has projections extending inward of the housing. The barrier is then threaded into the hearing aid shell. This design was a significant improvement over devices prior thereto.
Nevertheless, threading the barrier to the hearing aid requires additional mechanical components or alteration of the shell to effect the attachment.
Thus, there continues to be a need for hearing aid ear wax barriers which are easily inserted and removed without additional mechanical components and/or shell alterations. Preferably, such barriers would also provide an effective configuration for preventing the migration of ear wax into the hearing aid.